Coffee filter



Nov. 17, 1936. o. vo1sr GOFFEE FILTER Fi led llay 7, 1936 45 for conductlng awy the bottom filtrate.

Patenfed Nov. 17, 1936 A'I-ES PATENT I7FFICE COFFEE FEI'E'R Genmany Applica'tion May 7,

1936, Serie! N0. 78,295

In Germany December 27, 1933 4 Cla.ims.

The present lnvention relates to lmprovements ln cofiee-filter. Filters of thls clas's afiord-an egreeable use since they may, before belng placed on the vessel lntendeil for taklng up the liquid 5 filtered. be placed with thelr flat botbom on the tableso tha.t fllter pa.per and ground coflee or the like can be lntroduced wlthout difilculty. 'I'hey are furtlner immersed but 's1lghtly in the re- :elvlng vessel so that the latter is completely fllled upon filtering.

There have been known filters of thls class the lnner slde wall cf whlch ls provided with discharge channels e.nd the bottom cf which in'the mlddle ls provlded wlth dischargeholes. The

filtrate percolatlng through the lter paper on the slde Wall flows down l;hrough the channels of the side wa.ll and subsequently along the bottom towards the discherge holes thereof where it mixes wlth tlhe filtrate obtained on the bottom.

In such filters some difilculties a.re encoun tered in that the fllter paper lylng an the bottom interferes with the discharge of the slcle flltre.te. Efforbs have been made to obvlate this inconvenience by provicling the bottorn of the fllter vessel with ribs whlch keep the filter paper ab some dis- 5. These drawbacks are obvlated in the filter comstruqted according to the present lnvention inasmuch as the slde and bottom flltrates are dische.rged separately. This result is obtalned by providlng the inner surface 013 the side wall o1 the -illte1, whlch is 'preferably cf conical shape, wlth downward dlscherge channels running lnt'o diseharge holes in the bottom. whlch are lntended to.

recelve and pass oft the side flltrate only while other djscharge holes are provlded in the bottom The channels disposed an the lnner surf.ce of the 'filter well may be formed by downward rlbs proj esting from the latter a.nd leavingbetween them a plurallty cf channels each 01 whlch terminates 5 lnto a. separate bottom hole, or by grooves worked out In the plain funnel wa.ll ea.ch of whlch also ternt1lnates into a separate botfnm hole.

The filter accordlng to the inventlon ma.y also be composed of two parts. In thls lnstance lt 55 compflses a shell vessel perforated in the bottom only and an lnsert perforated in the bottom and in the side wa.ll and whichbetween its outslde and the lnsicle of the shell, leaves a hollow spece for the discharge cf the slde flltrate, the bottom of the insert so standing on the bottom of the shell vessel tha.t the slde and bottom filtrates are caused to fiow seperately through the bottom holes. A fllter paper may be interposed between the bottom of the lnsert end the bottom of the shell vessel. A fllter bag or a filter paper bag may also be interposed between the same. The bottom r1m of the insert may project downwards so that a hollow space is left below the lnserb bottom and above the filter paper placed on the bottom of the shell vessel. 'Ihis arrQngement will result in a better discharge of the bottom flltrate und in an accelerated flow of the bottom filtrate through the filter paper.

If a partlcularly pure filtrate ls to be obtained, a fllter pa.per or 2. fllter paper bag may be lnserted lnto the inner vessel a.nd an additional fllter paper may be lnterposed between the bottom of the insert and the bottom of the shell vessel.

' The two-part fllter may also be mede in such a way that the shell vessel is provlded. wlth a. detachable perforated bottom. In tlns instance, the shell vessel can be used elther wlthout a bottom or with a betteln. When be1ng used wlthout a bottom, the filter bag or filter paper bag ls inserted lnto the inner vessel only. When belng used wlth a bottom a filter paper may also be placed on the bottom. of the shell vessel.

The accompanylng drawing represents several embodlments of the lnventlon.

Flg. 1 shows a filter wlth channels in the side Wall anti with bottom holes, partly in section and partly in elevation.

Flg. 2 i s a section 'on line IIII of Flg. 1.

Fig. 3 shows a vertlcal section of another embodlment havlng a shell vessel and an insert.

Fig. 4 ls a sectlon on llne IVIV of Flg. 3, and

Fig. 5 sho ws a. vertlcal sectlon of a. modiflcation cf the filter accordlng to Figs. 3 anal 4.

Flg. 6 shows a, part vertlcal section of a further embodlment of the inventlon which represents a filter with a. shell vessel and an lnsert in which' the shell vessel ls provlded wlth a detachable bottom.

The fllter according to Flgs. 1 and 2 has the shape 01 a cup I with a. conlcal wall and with a handle 2. Near the bottom, the fllter vessel ls provlded with a. conlcal flange 3 whlch 1s lntended tor puttlng the fllter on the recelvlng vessel a.nd for placlng lt on the table'wlthout ehe underside 015 the fllter'cup being llable to pollution. On the worked out a plurallty of vertical or hel1cal grooves 5 betweeh which bearing su'rfaces 5 are left for supporting the fl1ter papet I. Euch groove 5 opens into a hole 8 in the filter bottom 9 which is moreovet provided with discharge holes I0 In any number desired.

The filter isused as follows:

. AI; first the filter cup 1s placed on the table, then the filter paper Is inserted and ground'cofiee is brought into the Inside space. Subsequently the filter is put on the receivihg vessel such as a coflee-pot and boiling water Is poured into the fllter. New the water will trickle through the ground coffeeyand flow' down along the side wall in the grooves and directly out through the bottom holes 8 as well as through the bottoms o1 the filter paper and the vessel so as to leave the latter through the holes I0. Thus the bottom filtrate and the side flltrate can flow out dlrectly.

without. difliculty.

In the filter according to Figs. 3 and 4 the outside vessel II has again the shape of a cup.

It is provided with a plurality of handles I2 which' clrcle of diScharge holes I5 for the side flltrate.

In the shell vessel II there is inserted a second vessel I6 of similar shape the wall of which Is provided w;th holes I'I for the side flltrate while the bottnm thereof Is pr0vided with holes I8 for the bottom flltrate. A sheet I5 of filter paper is interpo sed between the bottoms of the lnsert and the shell vessel respectively. Between these two vessels there may also be interposed a fllter bag or filter paper bag enclosing the whole lnsert.

In the filter according to Fig. 3 the bottom of the insert directly rests on the bottom o1 the shell vessel. As Is shown in Flg. 5, the insert vessel Is atits bottom end provided with a projectlng rim 20 so -that a. hollow space 2I is Ileft;

above the filter paper III. In the arrangement; shown by Fig. 5 the holes I4 and I8 need not register wlth one another and the filtrate can fiow out.without hindrance independently of the particular relative angular position 01 the 1nside and outside vessels.

The embodiments shown by Figs. 3 to 5 work in the same manner as the fllter cf Figs. 1 and.2. The diflerence however consists in that the single channels o1. the first embodiment. are replaced by a continuous hollow space encircling .the fitter vessela In the drawing the holes I I and I8 of the Inner vessel are represented on an exaggeratbed.

The filter constructed in a. icordance wiI:h F:Igs. 3 to 6 is ea sier to manufacture than the fllter provided wlth ribs or-grooves accorgllng to Fig. 1,

and more readily cleaned. On the other band, however, it requires two vessels. 'I'his is In part compensated by the possible economy in filter paper since, in case filter. paper is used, a. small fllter paper on the bottom will be suflclent.

F1g. 6 shows a further modlfication of the filtei deslg ned according to Flgs. 3 and 4. The Insert Hi ha.s.not been modifled, but is freely suspended in the shell vessel. The shell vessel II however is provided with a detachable'perforated bottom 2,061,119 Inslde of th wall l of the filter cup there are 22 which can be screwed on the shell vessel by means o! the thread 23 or be secured thereto in any other manner. 011 the bottom 22 a filter paper 24 ma.y be placed. Th1s can be used alone or in combination with a filter bag orfilter paper bag 25 placed into the insert. The filter paper 24 ma.y also be dispensed wlth. This embodiment affords the advantage.that in the case of a, single filtration the bottom 22 may be detached so that the bottom and side filtral:es are allowed to ran out quickly in a downward direction. On account of the very large number of holes I'I 01 the insert the side flltrate will fiow out therefrom readily and qulckly even i! no channels are provided In the inslde walls 015 the insert. 'I'his embodlment is particularly suited fdr la.rge fllters.

However, a. large number of chqnnels must then be provided to prevent the spaeing between the channels from being 1;oo large. v

Wh at I claim, is 1. A filtering vessel for cofiee or the like comprising an imperfor.te outef wall, means for re movably supporting said vessel upon a. receiving vessel so that the major portion of sa1d Wall is located above and outside of sid receiving vessel, a plurality 015 channel's a.t the Inside o1 said wall, and a. bottom, seid channels extending downwardly and throu'gh said bottom and having openings at thelr lower ends whereby when a filtering layer is insert'ed in sa1d filtering vessel adjacent sald channels and a. fluid. is filtered through Sa1d layer, the filtrate flowing downwardly thr ough seid channels passes 01T quickly through sa.id chaxinel openings.

2. A filtering vessel according to claim 1, said Wall being o-f frusto-conical shape, said channels extending in downward directlon, said bottom havlng perforatlons spaced from said wall whereby the filtrates flowing through. said channels and the flltrateS fiowing through the bottom of sa.id filtering layer are passed otI separately,

3. A flltering vessel accordihg to claim 1, said wa.l1 being of frusto-conical shape, the spaces intermediate adjacent cham1els formlng radially inwardly projectlng ribs adapted for supporting said fllterlng layer, sald channels and ribs extending in downward direction, sa.ld bottom be- Ing flat and having perforatlons spaced. from said wall, 'whereby the filtrates flowlng through said channels and the flltrates flowirig through the bottbm o! sald flltering layer are passed ofl separately.

4. A flltering vessel for cofl.ee or the llke comprislng an imperforate outer wall, an outwardiy extending flange on sald wall near the lower end thereof laut spaced therefrom and adapted tosupport said vessel upon a receiving vessel removably. downwardly extending rlbs at the Inside cf said Wall adapted fo'r supportingv a, flitzen,-

Ing layer thereon, seid rlb's forming channels therebetween for pa;ssing 01T the filtrate flowing through the sides of said filtering Iayer, and a bottom having a plurality of perforations there- 1n adjacenl; sald' wall, said channels termlnating directlylnto said perforations, and other perforations spaced from sald. wall whereby when a fluid Is filtered through sald layer the flltrates fiowlng through the sldes of sald layer and downwardly through said channels and the filtrates fiowing through the bottom of said filtering layer are -passed oft separately.

O'I'IOMAR VIGT. 

